Improvement in screw-presses



NITE STATES PATENT Trice.

THOMAS R. HOPKINS, OF PETERSBURG, VIRGINIA, ASSIGNOR TO HIMSELF AND R.E. ROBINSON, OF SAME PLAGE.

IMPROVEMENT IN SCREW-PRESSES.

Speciiication forming part of Letters Patent No. 25,l95, dated August23, 1859.

To aZZ whom it may concern:

Be it known that I, T. R. HOPKINS, of Petersburg, in the county ofDinwiddie and State of Virginia, have invented a new and usefulImprovement in Compound Screw and Lever Presses; and I do hereby declarethat the following is a full, clear, and exact description of the same,reference being had to the accompanying drawings, forming a part of thisspecicatiOn, in which- Figure l is a side'elevation of my improvedpress. Fig. 2 is a vertical central section in the line x :t of FigS.Fig. 3 is avertical central section in the line y y of Fig. '1. Figs. 4,5, 6, and 7 represent a modification of my press.

Similar letters of reference in each of the several iigures indicatecorresponding parts. The nature of my invention consists in operatingthe power-screw of a press or other machine by means of two nuts, whichare tted to gear with the thread of said screw, and so arranged andoperated upon that the upper one remains stationary while the lower onerevolves, and vice versa, this arrangement thus effecting a gradualprogression of the screw without causing the same to revolve with boththe back and forward movement of the actuating device.

As my invention is capable of being employed in combination with variousstyles of presses, and with different mechanical arrangements forcausing the upper nut to remain stationary while the lower one revolves,and vice versa, Ihave deemed it proper, for the better protection of myinterest, to show two methods of employing the same. I,how ever,shallonly describe the plan represented on the No. l Sheet.

AArepresent two upright pillars connected together by a base-plate orstationary platen, B, and an upper cross-piece, C.

D is a vertical screw. It extends down through the top cross-piece, andhas a follower, D', attached to its lower end, said follower moving upand down between the pillars, being kept in place by means of concavesockets formed in its ends to receive the circumference of the pillars.

E is a pivoted lever iitted loosely over the screw and turning on afulcrum at a, said lever being held up to the fulcrum by means of aspring, b, and guided at c by means of a slot in one of the pillars. Aspring, d, is attached to the front part of the lever, and arranged soas to bear against the bottoln ofthe slot c. This spring keeps thelever, always in operative condition, and acts against the upper nut ina manner to keep it cramped.

F F are two screw-nuts fitted over the power-screw, and constructed togear with the same. loosely in sockets d el of the lever E, and arefurnished each with a toothed flange, e e', of greater diameter thanthe.,sockets.

G G are two spring-barrels hung loosely on` an arbor, f. These barrelsareprovided each with a toothed flange, g g', which gear with thetoothed flanges of the nuts, as shown. The barrels have each ascroll-wound spring, h h', arranged in them, said springs being attachedby one of their ends to the inner circumference of the barrels, and bytheir other ends to the arbor j'.

H is aratchet-wheel arranged on the upper part of the arbor, and t aclick or pawl for taking hold of the teeth of said ratchet. By turningthe arbor with the knob j on its upper end the springs will be wound upso as to give out power, and said power` will be retained so far as therevolution of the arbor is concerned by means of the ratchet and pawl T.

T is a jointed connecting-rod attached to the loose end of lever E, andJ is a long-hand lever' pivoted to the lower end of said rod, and havingits resistance at K, as shown in the drawings.

From the above description of parts it will be evident, if the springsof the barrels are wound up and the upper nut is cramped by the actionof spring h, that when the main or hand lever is depressed the auxiliarylever E will descend with it, so as to cramp the lower nut and uncrampthe upper one. As soon as this occurs, the upper nut will be free torevolve, and the force of the spring in the upper barrel will cause itto turn and move down the screw a certain distance. By this time themain and auxiliary levers will have been elevated to their originalposition, and consequently the upper nut cramped, and the These nuts arecylindrical, and iitted p lower nut uncramped and left free to revolve,which it will be caused to do by the force of the spring in the lowerbarrel in a manner to continue the descent of the screw. rlhus theoperation continues until the follower has been caused to descend therequired distance to give the requisite pressure to the substance underit.

Having thus described my invention,l will, before stating my claim,remark that I do not limit myself to any particular means for actuatingthe nuts; but

I claim as my invention and desire to secure by Letters Patcnt- The use,in combination with a power-screw of a'press or other machine, of tworevolving nuts, F F, which are fitted to gear into the thread of saidscrew, and so arranged and operated upon in order to give motion to thescrew that the upper one'remains stationary Trios. R. HOPKINS.

Witnesses:

Tno. S. PLnAsANTs, Jos. VAN HoLLNAsI-I.

